1/* SPDX-License-Identifier: GPL-2.0 */
 2#ifndef _ASM_UM_BARRIER_H_
 3#define _ASM_UM_BARRIER_H_
 4
 5#include <asm/cpufeatures.h>
 6#include <asm/alternative.h>
 
 
 
 
 
 
 7
 8/*
 9 * Force strict CPU ordering.
10 * And yes, this is required on UP too when we're talking
11 * to devices.
12 */
13#ifdef CONFIG_X86_32
14
15#define mb()	alternative("lock; addl $0,0(%%esp)", "mfence", X86_FEATURE_XMM2)
16#define rmb()	alternative("lock; addl $0,0(%%esp)", "lfence", X86_FEATURE_XMM2)
17#define wmb()	alternative("lock; addl $0,0(%%esp)", "sfence", X86_FEATURE_XMM)
18
19#else /* CONFIG_X86_32 */
20
21#define mb()	asm volatile("mfence" : : : "memory")
22#define rmb()	asm volatile("lfence" : : : "memory")
23#define wmb()	asm volatile("sfence" : : : "memory")
24
25#endif /* CONFIG_X86_32 */
26
27#include <asm-generic/barrier.h>
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
28
29#endif

 
 1#ifndef _ASM_UM_BARRIER_H_
 2#define _ASM_UM_BARRIER_H_
 3
 4#include <asm/asm.h>
 5#include <asm/segment.h>
 6#include <asm/cpufeature.h>
 7#include <asm/cmpxchg.h>
 8#include <asm/nops.h>
 9
10#include <linux/kernel.h>
11#include <linux/irqflags.h>
12
13/*
14 * Force strict CPU ordering.
15 * And yes, this is required on UP too when we're talking
16 * to devices.
17 */
18#ifdef CONFIG_X86_32
19
20#define mb()	alternative("lock; addl $0,0(%%esp)", "mfence", X86_FEATURE_XMM2)
21#define rmb()	alternative("lock; addl $0,0(%%esp)", "lfence", X86_FEATURE_XMM2)
22#define wmb()	alternative("lock; addl $0,0(%%esp)", "sfence", X86_FEATURE_XMM)
23
24#else /* CONFIG_X86_32 */
25
26#define mb()	asm volatile("mfence" : : : "memory")
27#define rmb()	asm volatile("lfence" : : : "memory")
28#define wmb()	asm volatile("sfence" : : : "memory")
29
30#endif /* CONFIG_X86_32 */
31
32#define read_barrier_depends()	do { } while (0)
33
34#ifdef CONFIG_SMP
35
36#define smp_mb()	mb()
37#ifdef CONFIG_X86_PPRO_FENCE
38#define smp_rmb()	rmb()
39#else /* CONFIG_X86_PPRO_FENCE */
40#define smp_rmb()	barrier()
41#endif /* CONFIG_X86_PPRO_FENCE */
42
43#ifdef CONFIG_X86_OOSTORE
44#define smp_wmb()	wmb()
45#else /* CONFIG_X86_OOSTORE */
46#define smp_wmb()	barrier()
47#endif /* CONFIG_X86_OOSTORE */
48
49#define smp_read_barrier_depends()	read_barrier_depends()
50#define set_mb(var, value) do { (void)xchg(&var, value); } while (0)
51
52#else /* CONFIG_SMP */
53
54#define smp_mb()	barrier()
55#define smp_rmb()	barrier()
56#define smp_wmb()	barrier()
57#define smp_read_barrier_depends()	do { } while (0)
58#define set_mb(var, value) do { var = value; barrier(); } while (0)
59
60#endif /* CONFIG_SMP */
61
62/*
63 * Stop RDTSC speculation. This is needed when you need to use RDTSC
64 * (or get_cycles or vread that possibly accesses the TSC) in a defined
65 * code region.
66 *
67 * (Could use an alternative three way for this if there was one.)
68 */
69static inline void rdtsc_barrier(void)
70{
71	alternative(ASM_NOP3, "mfence", X86_FEATURE_MFENCE_RDTSC);
72	alternative(ASM_NOP3, "lfence", X86_FEATURE_LFENCE_RDTSC);
73}
74
75#endif